420
FXUS64 KHUN 080807
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
307 AM CDT TUE SEP 8 2026
..NEW NEAR TERM
KEY MESSAGES
UPDATED AT 307 AM CDT TUE SEP 8 2026
- LOW CHANCES FOR SHOWERS AND THUNDERSTORMS WILL RETURN TO THE
NORTHERN PART OF THE FORECAST AREA THURSDAY AND THURSDAY NIGHT.
- AS A MOIST AIRMASS RETURNS TO THE REGION, CHANCES FOR SHOWERS
AND THUNDERSTORMS WILL INCREASE TO 40-60% ON FRIDAY/SATURDAY
AFTERNOONS, BEFORE FALLING INTO THE 20-40% RANGE SUNDAY/MONDAY.
LIGHTNING AND HEAVY RAINFALL WILL BE THE MAIN IMPACTS FROM THE
STORMS.
- NWS HEAT RISK WILL REMAIN IN THE MINOR TO MODERATE CATEGORY
THROUGHOUT THE FORECAST PERIOD.
NEAR TERM
(TODAY)
ISSUED AT 307 AM CDT TUE SEP 8 2026
A FRONTAL BOUNDARY THAT MOVED SOUTHWARD ACROSS THE AREA A COUPLE
OF DAYS AGO HAS MOVED EVEN FURTHER TO THE SOUTH, NOW EXTENDING
FROM THE CENTRAL GREAT PLAINS, TO THE MS/AL COAST AND ACROSS
CENTRAL FLORIDA. BROAD HIGH PRESSURE SITUATED OVER THE MID
ATLANTIC WAS THE OTHERWISE CONTROLLING THE AREA'S GENERAL
WEATHER. A SE FLOW ROUNDING THIS HIGH WAS BRINGING LOW/MID LEVEL
MOISTURE ACROSS THE REGION. THIS WAS NOTED WELL FROM THE OLD LONG-
SHORT IMAGE, AND NIGHTTIME MICROPHYSICS SATELLITE PRODUCTS. THIS
WAS PRODUCING SCATTERED LOW/MID ALTITUDE CLOUDS ACROSS THE AREA.
A GENERALLY SE FLOW HAS RETURNED ACROSS THE AREA, AS THE HIGH
SLOWLY BUILDS MORE OFF SHORE THE NEXT COUPLE OF DAYS. OTHERWISE,
TEMPERATURES WERE IN THE 70S WITH SE WINDS OF 5-10 MPH.
THE ABOVE NOTED MOISTURE BEING LIFTED ALONG WITH DAYTIME HEATING
PRODUCED INSTABILITY COULD RESULT IN A FEW SHOWERS MAINLY THIS
AFTERNOON. WILL STAY WITH 20 PERCENT OR LESS RAIN CHANCES. WITH A
COOLER AIRMASS IN PLACE, HIGH TEMPERATURES SHOULD BE SIMILAR TO
WHAT OCCURRED ON LABOR DAY, RANGING FROM THE UPPER 80S TO LOWER
90S. EXPECT SE WINDS OF 5-15 MPH THIS MORNING AND AFTERNOON,
DECREASING BELOW 5 MPH AFTER SUNSET.
SHORT TERM
(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 1105 PM CDT MON SEP 7 2026
SHORT RANGE MODEL CONSENSUS SUGGESTS THAT THE TN VALLEY WILL
REMAIN UNDER THE INFLUENCE OF A STRONG 500-MB RIDGE DURING THE
PERIOD FROM TUESDAY NIGHT-WEDNESDAY NIGHT, AS ITS CENTER MIGRATES
SLOWLY EASTWARD INTO THE SOUTHEASTERN ATLANTIC COAST. AT THE
SURFACE, A WEAKENING DOME OF HIGH PRESSURE WILL SHIFT SLOWLY
EASTWARD OFF THE MID-ATLANTIC COAST, BUT SHOULD PROVIDE SUFFICIENT
INFLUENCE TO SUSTAIN LIGHT SSE WINDS AND A PLUME OF RELATIVELY
LOWER DEWPOINTS ACROSS OUR REGION. THIS WILL TRANSLATE TO A
CONTINUATION OF DRY WEATHER, WITH MORNING LOWS IN THE U60S-L70S
(PERHAPS A FEW DEGREES COOLER IN THE SHELTERED VALLEYS OF
NORTHEAST AL/SOUTHERN TN) AS AFTERNOON HIGHS RISE BACK INTO THE
L-M 90S (WITH LESS MORNING CLOUD COVER).
BY THURSDAY AND THURSDAY NIGHT, THE SUBTROPICAL RIDGE IS
PREDICTED TO WEAKEN AND SHIFT EASTWARD INTO THE SOUTHWESTERN NORTH
ATLANTIC, ALLOWING A LIGHT WSW FLOW TO DEVELOP ALOFT. AS THIS
OCCURS, LIGHT SW FLOW WILL BECOME ESTABLISHED IN THE LOW-LEVELS
AHEAD OF A COLD FRONT (ATTACHED TO AN OCCLUDING CYCLONE ACROSS
NORTHERN QUEBEC) THAT WILL INITIALLY EXTEND FROM EASTERN CO
NORTHEASTWARD INTO SOUTHEASTERN QUEBEC. ALTHOUGH THE FRONT WILL
EXHIBIT VERY LITTLE (IF ANY) MOVEMENT, A PREFRONTAL WIND SHIFT
AXIS WILL FOCUS THE DEVELOPMENT OF WIDESPREAD CONVECTION (WELL TO
OUR NORTH) ON WEDNESDAY NIGHT AND THURSDAY, WHICH SHOULD FORCE THE
PREFRONTAL WIND SHIFT AXIS TO DRIFT SOUTHEASTWARD WITH TIME. THIS
FEATURE WILL LIKELY INITIATE NEW CLUSTERS OF SHOWERS AND
THUNDERSTORMS AS IT SLOWLY APPROACHES OUR CWFA, BUT WITH A VERY
LOW PROBABILITY THAT IT WILL ACTUALLY ENTER OUR REGION, WE WILL
ONLY INCLUDE A 20-30% POP (GENERALLY FOCUSED ACROSS NORTHWEST
AL/SOUTHERN TN). DUE TO THE LINGERING PRESENCE OF A DRIER (BUT
GRADUALLY MODIFYING) CONTINENTAL AIRMASS ACROSS OUR REGION, CAPE
WILL BE ON THE LOW SIDE (BUT CERTAINLY ADEQUATE FOR DEVELOPMENT OF
SOME THUNDERSTORMS). THIS, COUPLED WITH WEAK VERTICAL WIND SHEAR,
SUGGEST THAT ANY STORMS WILL BE UNORGANIZED AND LIGHTNING SHOULD
BE THE PRIMARY IMPACT. HIGHS WILL REMAIN IN THE L-M 90S ON
THURSDAY, WITH OVERNIGHT LOWS ONCE AGAIN IN THE U60S-L70S.
LONG TERM
(FRIDAY THROUGH MONDAY)
ISSUED AT 1105 PM CDT MON SEP 7 2026
EXTENDED RANGE MODEL DATA SUGGESTS THAT A SUBTLE LOW-LEVEL
STREAMLINE CONFLUENCE AXIS (INITIALLY POSITIONED ACROSS THE TN
VALLEY) WILL LIFT NORTHWARD INTO THE OH VALLEY AND LOSE DEFINITION
DURING THE PERIOD FROM FRIDAY-SATURDAY NIGHT, IN RESPONSE TO
SURFACE PRESSURE FALLS ACROSS THE SOUTHERN HIGH PLAINS. THIS,
ALONG WITH SW FLOW ALOFT (PROVIDED BY A WEAK MID- LEVEL TROUGH
DRIFTING EASTWARD OVER THE LOWER MS VALLEY), WILL FORCE PWAT
VALUES BACK INTO THE 1.8-2" RANGE, LEADING TO A GENERAL INCREASE
IN THE COVERAGE OF SHOWERS AND THUNDERSTORMS BOTH DAYS. WITH NO
CLEAR EVIDENCE OF SYNOPTIC SCALE FORCING FOR ASCENT, SUBTLE DEEP-
LAYER WARM/MOIST ADVECTION AND MESOSCALE BOUNDARIES WILL LIKELY BE
THE SOURCE OF UNORGANIZED CONVECTION (LARGELY TIED TO THE DIURNAL
WARMING CYCLE, BUT WITH SOME POTENTIAL FOR CONVECTION TO PERSIST
AT NIGHT, AS WELL).
ON SUNDAY AND MONDAY, THERE ARE INDICATIONS THAT THE ATLANTIC
SUBTROPICAL RIDGE WILL BEGIN TO STRENGTHEN AS IT RETROGRADES
WESTWARD INTO THE SOUTHEASTERN CONUS. ALTHOUGH THIS COULD
POTENTIALLY HAVE A NEGATIVE INFLUENCE ON THE OVERALL COVERAGE OF
AFTERNOON CONVECTION, LOW-LEVEL MOISTURE RETURN WILL IMPROVE AS
SOUTHERLY FLOW BECOMES ESTABLISHED WITHIN THE WARM SECTOR OF A LOW
TRACKING NORTHEASTWARD INTO THE UPPER MS VALLEY. WITH DEWPOINTS
RETURNING TO THE L-M 70S, PWAT VALUES WILL CONTINUE TO RISE ABOVE
2" AND THIS COUPLED WITH COLLAPSING STEERING CURRENTS ALOFT MAY
ENHANCE THE RISK FOR LOCALLY HEAVY RAINFALL AND FLOODING DURING
THIS PERIOD. DUE TO INCREASED RAIN CHANCES, HIGHS WILL FALL BACK
INTO THE U80S-L90S, AS OVERNIGHT LOWS REMAIN IN THE U60S-L70S.
AVIATION
(06Z TAFS)
ISSUED AT 1252 AM CDT TUE SEP 8 2026
THERE HAVE BEEN NO CHANGES TO PREVIOUS AVIATION FORECAST
REASONING, AS A LOWER DECK OF BROKEN STRATOCUMULUS CLOUDS WILL
CONTINUE TO EXPAND NORTHWESTWARD INTO THE REGION EARLY THIS
MORNING. THIS WILL PROVIDE VFR CIGS ARND 5 KFT (AND PERHAPS A FEW
SPRINKLES OF RAIN OR LGT SHRA) THAT SHOULD PERSIST THRU EARLY-MID
AFTN BEFORE DISPERSING. SE SURFACE FLOW WILL INCREASE TO 10G18
KTS BEGINNING ARND 14Z, BUT SHOULD SUBSIDE BY SUNSET.
HUN WATCHES/WARNINGS/ADVISORIES
AL...NONE.
TN...NONE.
NEAR TERM...RSB
SHORT TERM....70/DD
LONG TERM....70/DD
AVIATION...70/DD
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